Sherbrooke Research and Development Centre, Agriculture and Agri-Food Canada, Sherbrooke, QC J1M 0C8, Canada.
Department of Animal Science, McGill University, Ste-Anne-De-Bellevue, QC H9X 3V9, Canada.
Genes (Basel). 2021 Oct 28;12(11):1727. doi: 10.3390/genes12111727.
Milk fat and protein contents are among key elements of milk quality, and they are attracting more attention in response to consumers' demand for high-quality dairy products. To investigate the potential regulatory roles of DNA methylation underlying milk component yield, whole genome bisulfite sequencing was employed to profile the global DNA methylation patterns of mammary gland tissues from 17 Canada Holstein cows with various milk fat and protein contents. A total of 706, 2420 and 1645 differentially methylated CpG sites (DMCs) were found between high vs. low milk fat (HMF vs. LMF), high vs. low milk protein (HMP vs. LMP), and high vs. low milk fat and protein (HMFP vs. LMFP) groups, respectively ( value < 0.1). Twenty-seven, 56 and 67 genes harboring DMCs in gene regions (denoted DMC genes) were identified for HMF vs. LMF, HMP vs. LMP and HMFP vs. LMFP, respectively. DMC genes from HMP vs. LMP and HMFP vs. LMFP comparisons were significantly overrepresented in GO terms related to aerobic electron transport chain and/or mitochondrial ATP (adenosine triphosphate) synthesis coupled electron transport. A total of 83 (HMF vs. LMF), 708 (HMP vs. LMP) and 408 (HMFP vs. LMFP) DMCs were co-located with 87, 147 and 158 quantitative trait loci (QTL) for milk component and yield traits, respectively. In conclusion, the identified methylation changes are potentially involved in the regulation of milk fat and protein yields, as well as the variation in reported co-located QTLs.
乳脂肪和蛋白质含量是牛奶质量的关键因素之一，它们正吸引着越来越多的关注，以满足消费者对高质量乳制品的需求。为了研究 DNA 甲基化在牛奶成分产量中的潜在调节作用，我们对 17 头具有不同乳脂肪和蛋白质含量的加拿大荷斯坦奶牛的乳腺组织进行了全基因组亚硫酸氢盐测序，以描绘其全基因组 DNA 甲基化模式。在高 vs. 低乳脂肪（HMF vs. LMF）、高 vs. 低乳蛋白（HMP vs. LMP）和高 vs. 低乳脂肪和蛋白（HMFP vs. LMFP）组之间，共发现了 706、2420 和 1645 个差异甲基化 CpG 位点（DMCs）（ 值 < 0.1）。在 HMF vs. LMF、HMP vs. LMP 和 HMFP vs. LMFP 组中，分别有 27、56 和 67 个基因含有 DMC 基因（称为 DMC 基因）。在 HMP vs. LMP 和 HMFP vs. LMFP 比较中，DMC 基因在与有氧电子传递链和/或线粒体 ATP（三磷酸腺苷）合成偶联电子传递相关的 GO 术语中显著过代表。在 HMF vs. LMF、HMP vs. LMP 和 HMFP vs. LMFP 中，共有 83、708 和 408 个 DMC 分别与 87、147 和 158 个与牛奶成分和产量性状相关的数量性状位点（QTL）共定位。总之，鉴定到的甲基化变化可能参与了乳脂肪和蛋白质产量的调控，以及报道的共定位 QTL 的变异。
